At present granular material, especially sand, is processed and separated into classes at the place of further processing of such granular material.
In U.S. Pat. No. 2,587,531 sampling of sand and separation thereafter into classes is disclosed.
U.S. Pat. No. 3,631,337 and 4,262,429 relates to drying of granular material.
It is an object of the present invention to improve upon the mentioned prior art.
It is another object to provide an installation for the extraction of granular material, which delivers such granular material in a desired composition to a transport means for transporting the granular material.
Further, the present invention provides a passive mixing unit for thoroughly mixing granular material, which uses little power and requires little service, as the mixing unit has no moving parts whatsoever.
It is preferred that the mixing unit is utilized in the noted installation for the extraction of granular material, as this mixing unit provides thorough mixing, which is required before taking samples of the mixture.
Further, the present invention provides a method and means for measuring the water content in granular material, which provides the exact content of so-called "dry material" of the mixture of water and granular material and therefor the value of this mixture.